1. Field of the Invention
The present invention relates to an electrical contact, and more particularly to a high-density socket connector contact for electrical interconnection of an electrical interface such as a central processing unit (CPU) with another electrical interface such as a printed circuit board (PCB).
2. Description of the Prior Art
Generally, an engaging portion of a socket connector contact is exposed to air prior to the socket connector being used. The engaging portion is easily oxidized, and a layer of oxidizing film forms and covers the engaging portion. This can decrease of the integrity of signal transmission through the contact. One way to resolve this problem, it is to use a contact which wipes the layer of oxidizing film off from the engaging portion when the contact is mated with a mating conductive member.
A commonly used wiping means is disclosed in FIG. 4. An LGA (land grid array) type socket connector contact 60 comprises a resilient cantilever 62 with a distal mating portion 64. During mating of the contact 60 with a mating conductive pad 80 of an IC package (not shown), the mating portion 64 wipes a bottom surface of the pad 80, thereby removing any oxidizing films that may have formed on the mating portion 64 and the bottom surface of the pad 80. Thus, unimpeded electrical engagement between the pad 80 and the contact 60 is provided.
The configuration of the cantilever 62 determines not only a horizontal wiping distance of the bottom surface of the pad 80 when the contact 60 mates with the pad 80, but also design parameters of the contact 60 such as mating force, wear and stress on the cantilever 62. In configuring the cantilever 62, all these factors need to be considered together. It is common for a good wiping configuration to be obtained only at the expense of one or more of the other factors. That is, it is very difficult to provide a cantilever 62 having an overall optimal configuration including good wiping characteristics. U.S. Pat. Nos. 5,139,427, 5,259,769, 5,378,160, 5,820,389 and 6,193,523 all disclose wiping means similar to those described above, and each of these patents manifest the problems of optimal configuring as described above.
Accordingly, a new electrical contact that overcomes the above disadvantages is desired.